Mark Mallory | Acadia University (original) (raw)

Papers by Mark Mallory

Ecotoxicology and Environmental Safety

Some Arctic food web structures are being affected by climate change with potential consequences ... more Some Arctic food web structures are being affected by climate change with potential consequences for long-term trends of environmental contaminants. We examined the effects of changes in trophic position of an Arctic-breeding seabird, the thick-billed murre (Uria lomvia), on declining rates of six major organochlorines (hexachlorobenzene, heptachlor epoxide, oxychlordane, dieldrin, p,p'-DDE and Σ69PCB) at two breeding colonies in the Canadian Arctic, one in northern Hudson Bay and one in the high Arctic. As a result of a change in diet, murres breeding in Hudson Bay lowered their trophic position during 1993-2013. After adjusting for the change in trophic position using egg δ(15)N values, the rates of decline in concentrations of all six organochlorines were reduced in the Hudson Bay murre eggs. In contrast, the murres at the high Arctic colony experienced an increase in trophic position which resulted in an increase in the rates of decline for all adjusted concentrations, excep...

Marine Pollution Bulletin, 2015

We provide the first report on winter concentrations of 32 trace metals from dovekies (Alle alle)... more We provide the first report on winter concentrations of 32 trace metals from dovekies (Alle alle), a small, Arctic seabird that has a seasonal shift in diet from small zooplankton in the breeding season to larger zooplankton and small fish in the non-breeding season. Concentrations of selected trace elements, as well as stable carbon (d 13 C) and nitrogen (d 15 N) isotope concentrations for a sample of 25 dovekies, were similar between adult males and females, and there was evidence that dovekies feeding at higher trophic levels had higher hepatic Hg. We also found plastic debris in nine of 65 (14%) gizzards examined. Our study helps provide a more complete picture of the foraging ecology and contaminant profile of dovekies, an important species in Arctic marine food webs.

PLoS ONE, 2014

The ivory gull (Pagophila eburnea) is an endangered seabird that spends its entire year in the Ar... more The ivory gull (Pagophila eburnea) is an endangered seabird that spends its entire year in the Arctic environment. In the past three decades, threats from various sources have contributed to a .70% decline in Canada. To assess the annual habitat needs of this species, we attached satellite transmitters to 12 ivory gulls on Seymour Island, Nunavut in 2010, which provided up to four breeding seasons of tracking data. Analysis of migratory behaviour revealed considerable individual variation of post-breeding migratory route selection. Ivory gulls traveled a median of 74 days during post-breeding migration, but only 18 days during pre-breeding migration. In contrast to predictions, ivory gulls did not use the Greenland coast during migratory periods. Ivory gulls overwintered near the ice edge in Davis Strait, but also used the Labrador Sea in late February and March. We suggest that the timing of formation and recession and extent of sea ice plays a large role in ivory gull distribution and migratory timing.

Science of The Total Environment, 2014

Polynyas are recurring sites of open water in polar marine areas • Mercury (Hg) biomagnification ... more Polynyas are recurring sites of open water in polar marine areas • Mercury (Hg) biomagnification was studied in a small polynya near Nasaruvaalik Island, NU, Canada • Hg biomagnification estimates for invertebrates to fish were low compared to other Arctic systems • Factors underlying this result are unknown but may relate to primary productivity in small polynyas a b s t r a c t Recurring polynyas are important areas of biological productivity and feeding grounds for seabirds and mammals in the Arctic marine environment. In this study, we examined food web structure (using carbon and nitrogen isotopes, δ 13 C and δ 15 N) and mercury (Hg) bioaccumulation and biomagnification in a small recurring polynya ecosystem near Nasaruvaalik Island (Nunavut, Canada). Methyl Hg (MeHg) concentrations increased by more than 50-fold from copepods (Calanus hyperboreus) to Arctic terns (Sterna paradisaea), the abundant predators at this site. The biomagnification of MeHg through members of the food webusing the slope of log MeHg versus δ 15 Nwas 0.157 from copepods (C. hyperboreus) to fish. This slope was higher (0.267) when seabird chicks were included in the analyses. Collectively, our results indicate that MeHg biomagnification is occurring in this small polynya and that its trophic transfer is at the lower end of the range of estimates from other Arctic marine ecosystems. In addition, we measured Hg concentrations in some poorly studied members of Arctic marine food webs [e.g. Arctic alligatorfish (Ulcina olrikii) and jellyfish, Medusozoa], and found that MeHg concentrations in jellyfish were lower than expected given their trophic position. Overall, these findings provide fundamental information about food web structure and mercury contamination in a small Arctic polynya, which will inform future research in such ecosystems and provide a baseline against which to assess changes over time resulting from environmental disturbance.

Marine Pollution Bulletin, 2014

Marine birds have been found to ingest plastic debris in many of the world&am... more Marine birds have been found to ingest plastic debris in many of the world's oceans. Plastic accumulation data from necropsies findings and regurgitation studies are presented on 13 species of marine birds in the North Atlantic, from Georgia, USA to Nunavut, Canada and east to southwest Greenland and the Norwegian Sea. Of the species examined, the two surface plungers (great shearwaters Puffinus gravis; northern fulmars Fulmarus glacialis) had the highest prevalence of ingested plastic (71% and 51%, respectively). Great shearwaters also had the most pieces of plastics in their stomachs, with some individuals containing as many of 36 items. Seven species contained no evidence of plastic debris. Reporting of baseline data as done here is needed to ensure that data are available for marine birds over time and space scales in which we see changes in historical debris patterns in marine environments (i.e. decades) and among oceanographic regions.

Environment International, 2014

We examined basic breeding biology, as well as the eVects of parental sex, brood size, nestling a... more We examined basic breeding biology, as well as the eVects of parental sex, brood size, nestling age, and nest habitat on foraging distances and parental food delivery rates of snow buntings (Plectrophenax nivalis) on Devon Island, NT, Canada, in the summers of 2003-2006. Clutch sizes and initiation dates were similar to those found in previous studies, although nest density was much higher. Feeding rates and foraging distances of buntings diVered depending on the size and age of the brood, but were similar between nest habitats. Unlike in earlier studies, we found that male buntings made fewer feeding visits, but traveled longer distances to forage for food than females. Whether these diVerences between the sexes relate to reducing competition for prey, or to diVering sex roles in parental care due to the poorly insulated nest cavities of this species, remains to be determined.

Plastic debris has become ubiquitous in the marine environment and seabirds may ingest debris whi... more Plastic debris has become ubiquitous in the marine environment and seabirds may ingest debris which can have deleterious effects on their health. In the North Atlantic Ocean, surface feeding seabirds typically ingest high levels of plastic, while the diving auks which feed in the water column typically have much lower levels. We examined 186 thick-billed murres from five colonies in the eastern Canadian Arctic for ingested plastic debris. Approximately 11% of the birds had at least one piece of plastic debris in their gastrointestinal tracts, with debris dominated by user plastics. This is the first report of ingested plastics in an auk species in Canada's Arctic, and the highest incidence of plastic ingestion to date for thick-billed murres (Uria lomvia).

Marine Pollution Bulletin, 2009

The role of northern fulmars (Fulmarus glacialis) was investigated for the transport of nutrients... more The role of northern fulmars (Fulmarus glacialis) was investigated for the transport of nutrients and trace elements to a series of 10 ponds located along a gradient of seabird influence below a fulmar colony in the high Arctic (Cape Vera, Devon Island, Canada). Phosphorus, Cd, K, Zn, and As were identified as seabird-derived elements, having both a high concentration in fulmar guano and a low concentration in background pond sediments (i.e., a high biogenic enrichment factor). Fluxes of these elements were highest in the pond closest to the colony and declined exponentially with distance. Sediments in several of the ponds exceeded Canadian Sediment Quality Guidelines for the Protection of Aquatic Life set for As (5.9 mg/kg) and Cd (0.6 mg/kg), and in the pond closest to the colony, which receives the most seabird subsidies, sediments contained 343 mg/kg Zn, exceeding the threshold for probable adverse biological effects. Although nutrient subsidies from fulmars create an Arctic oasis at Cape Vera, which supports a variety of flora and fauna, the same biological transport pathway puts at risk some of these species by creating sedimentary As, Cd, and Zn concentrations at this remote site similar to those usually observed only near industrialized locations.

A large seabird colony of northern fulmars (Fulmarus glacialis) at Cape Vera on Devon Island in t... more A large seabird colony of northern fulmars (Fulmarus glacialis) at Cape Vera on Devon Island in the Canadian high Arctic has been shown to act as an effective biological pump, transporting large quantities of marine-derived nutrients and contaminants to the ponds beneath their nesting sites. Previous research has shown that seabirds also have the potential to elevate radionuclide concentrations in their immediate surroundings. Here, we assess the influence of the Cape Vera seabird colony on the 210 Pb budgets of six affected ponds and one control site, and discuss potential implications with respect to 210 Pb dating methodologies. In general, fluxes of 210 Pb at Cape Vera were similar to, or less than, those measured at other Arctic locations not influenced by seabirds. Plots of unsupported 210 Pb activity versus depth showed a number of non-monotonic features in all sediment cores, necessitating the use of the constant-rate-of-supply (CRS) model to derive agedepth profiles. We conclude that seabird activity has not dramatically increased the 210 Pb flux to the ponds at Cape Vera. Overall, the low flux of excess 210 Pb made accurate dating problematic for some of the study cores, necessitating the use of independent dating markers (e.g., 137 Cs and PCB concentrations) to verify the reliability of the chronologies.

The use of seabirds as sentinels of the condition of aquatic ecosystems has been well-established... more The use of seabirds as sentinels of the condition of aquatic ecosystems has been well-established. Large environmental perturbations to aquatic food webs (e.g., chemical contamination, overfishing, particulate pollution) have all been detected or monitored by tracking seabirds at colonies. However, seabirds may elicit more subtle, sublethal responses that can also be used to track ecosystem health, or the health of seabird populations. In this article, we advocate for field researchers to plan a priori to collect a broader suite of samples when handling seabirds, and to reach out for collaboration with specialists (e.g., parasitologists, wildlife veterinarians). Collectively, such efforts will greatly improve our ability to establish baseline physiological and chemical levels for seabirds, against which we can detect future changes in aquatic ecosystems.

... Since the kittiwake is studied at many sites in the Atlantic (Frederiksen et al., 2005), it w... more ... Since the kittiwake is studied at many sites in the Atlantic (Frederiksen et al., 2005), it was possible to design a large-scale study involving colonies well dispersed throughout the breed-ing ... For coastal and shelf regions, we used large marine ecosystems (LMEs) (Sherman, 2006 ...

Environmental …, 2009

Systematic monitoring of seabird populations in Canada has been ongoing since the 1920s and the m... more Systematic monitoring of seabird populations in Canada has been ongoing since the 1920s and the monitoring of diets and other biological indicators of ecosystem change started in the 1970s. Long-term monitoring of population parameters began in the 1980s. These studies originally were conducted mainly by the Canadian Wildlife Service, but subsequently have involved several universities and nongovernment organization groups. We review the results of this monitoring from the 1970s onwards for six oceanographic regions to assess population trends among Canadian seabirds and correlated trends in diets, phenology, and other breeding biology variables. Within regions, trends in most variables studied have been broadly congruent, but there was often variation among regions. In particular, seabird populations in the Pacific coast zone affected by the California Current upwelling system have shown generally negative trends since the 1980s, whereas trends for populations of the same species to the north of this zone have been mainly positive. Likewise, on the east coast, trends at Arctic colonies have been decoupled from those at colonies around Newfoundland and in the Gulf of St. Lawrence, especially since the major cold water event of the early 1990s. Several long-term studies have shown an association between population events and diet and phenology changes. Diet and indicators of condition (chick growth, reproductive success) sometimes responded very rapidly to oceanic changes, making them excellent signals of ecosystem perturbations. The review highlights the effects of decadal-scale regime shifts on Canadian seabirds, confirms the value of long-term studies and supports the applicability of single-site observations to regional populations.

Environmental monitoring …, 2006

Marine birds are sensitive indicators of the condition of marine ecosystems in the Arctic, partly... more Marine birds are sensitive indicators of the condition of marine ecosystems in the Arctic, partly because they feed at the top of the arctic food chain. The Northern Ecosystem Initiative (NEI) recently supported four separate studies that investigated aspects of Arctic marine bird science which simultaneously addressed goals of the NEI to better understand northern ecosystems and their response to environmental stressors. The projects used both scientific and traditional knowledge to examine the relationship between sea-ice, contaminants, and the ecology of marine birds, and to transfer environmental knowledge to students. Results from these investigations confirm that changes are occurring in Arctic environments, and that these are captured through marine bird research. Collectively these studies provided new data that supported NEI objectives of monitoring the health of the Arctic ecosystem, and contributed to Canada's international obligations for Arctic science.

Hydrobiologia, 2009

Allochthonous nutrient subsidies play an important role in shaping biotic communities, particular... more Allochthonous nutrient subsidies play an important role in shaping biotic communities, particularly in naturally oligotrophic ecosystems such as those commonly found in the Canadian High Arctic. Seabirds have been identified as an important vector capable of transporting significant quantities of nutrients from marine to terrestrial environments. However, the influence of seabird-derived nutrients on water quality and ecosystem functioning of Arctic freshwater systems has been largely unexplored. Here, we sampled 24 ponds on Cape Vera, Devon Island (Nunavut, Arctic Canada), an area that is home to over 10,000 nesting pairs of northern fulmars (Fulmarus glacialis), in order to explore the influence of seabirds on water quality and diatom ecology. Our data reveal distinctive water chemistry changes (e.g., high pH, nutrients) and diatom assemblages (e.g., very low diversity) related to varying degrees of bird influence. Using d 15 N as a proxy of trophic level, we show that a small but significant portion of the variance in the diatom species data can be explained by seabird-derived nutrients. Although the generation of robust quantitative models predicting d 15 N from fossil diatom data was limited by the overwhelming dominance of a few taxa, this study provides evidence that seabird-derived nutrients play a critical role in influencing the water quality of Arctic ponds. Interestingly, diatom assemblage composition does not respond in a simple fashion to seabird-derived nutrients, in contrast to diatom-nutrient relationships recorded in many temperate regions.

Ecology and Society, 2007

Page 1. Copyright © 2007 by the author(s). Published here under license by the Resilience Allianc... more Page 1. Copyright © 2007 by the author(s). Published here under license by the Resilience Alliance. Gilchrist, G., and ML Mallory. 2007. Comparing expert-based science with local ecological knowledge: what are we afraid of? Ecology and Society 12(1): r1. ...

… of the Royal …, 2009

Migratory animals such as seabirds, salmon and whales can transport large quantities of nutrients... more Migratory animals such as seabirds, salmon and whales can transport large quantities of nutrients across ecosystem boundaries, greatly enriching recipient food webs. As many of these animals biomagnify contaminants, they can also focus pollutants at toxic ...

The Condor, 2009

Resumen. Los cronogramas de reproducción de las aves podrían no cambiar a una tasa suficientement... more Resumen. Los cronogramas de reproducción de las aves podrían no cambiar a una tasa suficientemente rápida como para seguir el patrón actual de cambio climático, lo que causaría una reducción en su éxito reproductivo. Esta perturbación de la sincronía se conoce como la "hipótesis del desajuste." Analizamos datos de la reproducción de Uria lomvia en la parte norte de la bahía de Hudson, Canadá, para examinar la importancia relativa del ajuste y desajuste temporal de la reproducción en determinar las tasas de crecimiento de los pichones. Entre 1988 y 2007, la fecha de ruptura y desaparición del hielo oceánico en las áreas circundantes se adelantó en 17 días, y la fecha en que los conteos de U. lomvia exhibieron un pico (un índice de la disponibilidad de alimento) se adelantó en la misma cantidad de tiempo. Sin embargo, la fecha mediana de postura de huevos se adelantó en sólo cinco días, de modo que el número de días entre la fecha de eclosión y las fechas de asistencia pico y de 50% de cobertura de hielo aumentó durante el período de estudio. El crecimiento de los pichones se redujo en aquellos años en los que los conteos de los adultos que los atendían presentaron picos a inicios de la temporada y temprano en relación con la fecha de eclosión. Estas observaciones sugieren que el momento en que tiene lugar la reproducción no se está adelantando para seguir la tasa de cambio de los eventos que suceden en el ambiente marino ártico, lo que conduce a una mayor dificultad en el aprovisionamiento de las crías. También demostramos que existe una relación entre el estado de la Oscilación del Atlántico Norte con la fecha de asistencia máxima de aves a la colonia, así como con el crecimiento de los pichones. Esto sugiere que las interacciones océano-atmósfera de gran escala influencian la disponibilidad de presas para U. lomvia, aunque el mecanismo a través del cual sucede esto todavía es desconocido. Nuestros resultados apoyan la idea de que el desajuste de los ciclos reproductivos de las aves con los picos en la abundancia de alimento es una consecuencia importante del cambio climático global.

Marine pollution bulletin, 2006

1. Mar Pollut Bull. 2006 Aug;52(8):978-82. Epub 2006 May 3. Elevated mercury levels in a declinin... more 1. Mar Pollut Bull. 2006 Aug;52(8):978-82. Epub 2006 May 3. Elevated mercury levels in a declining population of ivory gulls in the Canadian Arctic. Braune BM, Mallory ML, Gilchrist HG. Environment Canada, National Wildlife ...

Ecotoxicology and Environmental Safety

Some Arctic food web structures are being affected by climate change with potential consequences ... more Some Arctic food web structures are being affected by climate change with potential consequences for long-term trends of environmental contaminants. We examined the effects of changes in trophic position of an Arctic-breeding seabird, the thick-billed murre (Uria lomvia), on declining rates of six major organochlorines (hexachlorobenzene, heptachlor epoxide, oxychlordane, dieldrin, p,p'-DDE and Σ69PCB) at two breeding colonies in the Canadian Arctic, one in northern Hudson Bay and one in the high Arctic. As a result of a change in diet, murres breeding in Hudson Bay lowered their trophic position during 1993-2013. After adjusting for the change in trophic position using egg δ(15)N values, the rates of decline in concentrations of all six organochlorines were reduced in the Hudson Bay murre eggs. In contrast, the murres at the high Arctic colony experienced an increase in trophic position which resulted in an increase in the rates of decline for all adjusted concentrations, excep...

Marine Pollution Bulletin, 2015

We provide the first report on winter concentrations of 32 trace metals from dovekies (Alle alle)... more We provide the first report on winter concentrations of 32 trace metals from dovekies (Alle alle), a small, Arctic seabird that has a seasonal shift in diet from small zooplankton in the breeding season to larger zooplankton and small fish in the non-breeding season. Concentrations of selected trace elements, as well as stable carbon (d 13 C) and nitrogen (d 15 N) isotope concentrations for a sample of 25 dovekies, were similar between adult males and females, and there was evidence that dovekies feeding at higher trophic levels had higher hepatic Hg. We also found plastic debris in nine of 65 (14%) gizzards examined. Our study helps provide a more complete picture of the foraging ecology and contaminant profile of dovekies, an important species in Arctic marine food webs.

PLoS ONE, 2014

The ivory gull (Pagophila eburnea) is an endangered seabird that spends its entire year in the Ar... more The ivory gull (Pagophila eburnea) is an endangered seabird that spends its entire year in the Arctic environment. In the past three decades, threats from various sources have contributed to a .70% decline in Canada. To assess the annual habitat needs of this species, we attached satellite transmitters to 12 ivory gulls on Seymour Island, Nunavut in 2010, which provided up to four breeding seasons of tracking data. Analysis of migratory behaviour revealed considerable individual variation of post-breeding migratory route selection. Ivory gulls traveled a median of 74 days during post-breeding migration, but only 18 days during pre-breeding migration. In contrast to predictions, ivory gulls did not use the Greenland coast during migratory periods. Ivory gulls overwintered near the ice edge in Davis Strait, but also used the Labrador Sea in late February and March. We suggest that the timing of formation and recession and extent of sea ice plays a large role in ivory gull distribution and migratory timing.

Science of The Total Environment, 2014

Polynyas are recurring sites of open water in polar marine areas • Mercury (Hg) biomagnification ... more Polynyas are recurring sites of open water in polar marine areas • Mercury (Hg) biomagnification was studied in a small polynya near Nasaruvaalik Island, NU, Canada • Hg biomagnification estimates for invertebrates to fish were low compared to other Arctic systems • Factors underlying this result are unknown but may relate to primary productivity in small polynyas a b s t r a c t Recurring polynyas are important areas of biological productivity and feeding grounds for seabirds and mammals in the Arctic marine environment. In this study, we examined food web structure (using carbon and nitrogen isotopes, δ 13 C and δ 15 N) and mercury (Hg) bioaccumulation and biomagnification in a small recurring polynya ecosystem near Nasaruvaalik Island (Nunavut, Canada). Methyl Hg (MeHg) concentrations increased by more than 50-fold from copepods (Calanus hyperboreus) to Arctic terns (Sterna paradisaea), the abundant predators at this site. The biomagnification of MeHg through members of the food webusing the slope of log MeHg versus δ 15 Nwas 0.157 from copepods (C. hyperboreus) to fish. This slope was higher (0.267) when seabird chicks were included in the analyses. Collectively, our results indicate that MeHg biomagnification is occurring in this small polynya and that its trophic transfer is at the lower end of the range of estimates from other Arctic marine ecosystems. In addition, we measured Hg concentrations in some poorly studied members of Arctic marine food webs [e.g. Arctic alligatorfish (Ulcina olrikii) and jellyfish, Medusozoa], and found that MeHg concentrations in jellyfish were lower than expected given their trophic position. Overall, these findings provide fundamental information about food web structure and mercury contamination in a small Arctic polynya, which will inform future research in such ecosystems and provide a baseline against which to assess changes over time resulting from environmental disturbance.

Marine Pollution Bulletin, 2014

Marine birds have been found to ingest plastic debris in many of the world&am... more Marine birds have been found to ingest plastic debris in many of the world's oceans. Plastic accumulation data from necropsies findings and regurgitation studies are presented on 13 species of marine birds in the North Atlantic, from Georgia, USA to Nunavut, Canada and east to southwest Greenland and the Norwegian Sea. Of the species examined, the two surface plungers (great shearwaters Puffinus gravis; northern fulmars Fulmarus glacialis) had the highest prevalence of ingested plastic (71% and 51%, respectively). Great shearwaters also had the most pieces of plastics in their stomachs, with some individuals containing as many of 36 items. Seven species contained no evidence of plastic debris. Reporting of baseline data as done here is needed to ensure that data are available for marine birds over time and space scales in which we see changes in historical debris patterns in marine environments (i.e. decades) and among oceanographic regions.

Environment International, 2014

We examined basic breeding biology, as well as the eVects of parental sex, brood size, nestling a... more We examined basic breeding biology, as well as the eVects of parental sex, brood size, nestling age, and nest habitat on foraging distances and parental food delivery rates of snow buntings (Plectrophenax nivalis) on Devon Island, NT, Canada, in the summers of 2003-2006. Clutch sizes and initiation dates were similar to those found in previous studies, although nest density was much higher. Feeding rates and foraging distances of buntings diVered depending on the size and age of the brood, but were similar between nest habitats. Unlike in earlier studies, we found that male buntings made fewer feeding visits, but traveled longer distances to forage for food than females. Whether these diVerences between the sexes relate to reducing competition for prey, or to diVering sex roles in parental care due to the poorly insulated nest cavities of this species, remains to be determined.

Plastic debris has become ubiquitous in the marine environment and seabirds may ingest debris whi... more Plastic debris has become ubiquitous in the marine environment and seabirds may ingest debris which can have deleterious effects on their health. In the North Atlantic Ocean, surface feeding seabirds typically ingest high levels of plastic, while the diving auks which feed in the water column typically have much lower levels. We examined 186 thick-billed murres from five colonies in the eastern Canadian Arctic for ingested plastic debris. Approximately 11% of the birds had at least one piece of plastic debris in their gastrointestinal tracts, with debris dominated by user plastics. This is the first report of ingested plastics in an auk species in Canada's Arctic, and the highest incidence of plastic ingestion to date for thick-billed murres (Uria lomvia).

Marine Pollution Bulletin, 2009

The role of northern fulmars (Fulmarus glacialis) was investigated for the transport of nutrients... more The role of northern fulmars (Fulmarus glacialis) was investigated for the transport of nutrients and trace elements to a series of 10 ponds located along a gradient of seabird influence below a fulmar colony in the high Arctic (Cape Vera, Devon Island, Canada). Phosphorus, Cd, K, Zn, and As were identified as seabird-derived elements, having both a high concentration in fulmar guano and a low concentration in background pond sediments (i.e., a high biogenic enrichment factor). Fluxes of these elements were highest in the pond closest to the colony and declined exponentially with distance. Sediments in several of the ponds exceeded Canadian Sediment Quality Guidelines for the Protection of Aquatic Life set for As (5.9 mg/kg) and Cd (0.6 mg/kg), and in the pond closest to the colony, which receives the most seabird subsidies, sediments contained 343 mg/kg Zn, exceeding the threshold for probable adverse biological effects. Although nutrient subsidies from fulmars create an Arctic oasis at Cape Vera, which supports a variety of flora and fauna, the same biological transport pathway puts at risk some of these species by creating sedimentary As, Cd, and Zn concentrations at this remote site similar to those usually observed only near industrialized locations.

A large seabird colony of northern fulmars (Fulmarus glacialis) at Cape Vera on Devon Island in t... more A large seabird colony of northern fulmars (Fulmarus glacialis) at Cape Vera on Devon Island in the Canadian high Arctic has been shown to act as an effective biological pump, transporting large quantities of marine-derived nutrients and contaminants to the ponds beneath their nesting sites. Previous research has shown that seabirds also have the potential to elevate radionuclide concentrations in their immediate surroundings. Here, we assess the influence of the Cape Vera seabird colony on the 210 Pb budgets of six affected ponds and one control site, and discuss potential implications with respect to 210 Pb dating methodologies. In general, fluxes of 210 Pb at Cape Vera were similar to, or less than, those measured at other Arctic locations not influenced by seabirds. Plots of unsupported 210 Pb activity versus depth showed a number of non-monotonic features in all sediment cores, necessitating the use of the constant-rate-of-supply (CRS) model to derive agedepth profiles. We conclude that seabird activity has not dramatically increased the 210 Pb flux to the ponds at Cape Vera. Overall, the low flux of excess 210 Pb made accurate dating problematic for some of the study cores, necessitating the use of independent dating markers (e.g., 137 Cs and PCB concentrations) to verify the reliability of the chronologies.

The use of seabirds as sentinels of the condition of aquatic ecosystems has been well-established... more The use of seabirds as sentinels of the condition of aquatic ecosystems has been well-established. Large environmental perturbations to aquatic food webs (e.g., chemical contamination, overfishing, particulate pollution) have all been detected or monitored by tracking seabirds at colonies. However, seabirds may elicit more subtle, sublethal responses that can also be used to track ecosystem health, or the health of seabird populations. In this article, we advocate for field researchers to plan a priori to collect a broader suite of samples when handling seabirds, and to reach out for collaboration with specialists (e.g., parasitologists, wildlife veterinarians). Collectively, such efforts will greatly improve our ability to establish baseline physiological and chemical levels for seabirds, against which we can detect future changes in aquatic ecosystems.

... Since the kittiwake is studied at many sites in the Atlantic (Frederiksen et al., 2005), it w... more ... Since the kittiwake is studied at many sites in the Atlantic (Frederiksen et al., 2005), it was possible to design a large-scale study involving colonies well dispersed throughout the breed-ing ... For coastal and shelf regions, we used large marine ecosystems (LMEs) (Sherman, 2006 ...

Environmental …, 2009

Systematic monitoring of seabird populations in Canada has been ongoing since the 1920s and the m... more Systematic monitoring of seabird populations in Canada has been ongoing since the 1920s and the monitoring of diets and other biological indicators of ecosystem change started in the 1970s. Long-term monitoring of population parameters began in the 1980s. These studies originally were conducted mainly by the Canadian Wildlife Service, but subsequently have involved several universities and nongovernment organization groups. We review the results of this monitoring from the 1970s onwards for six oceanographic regions to assess population trends among Canadian seabirds and correlated trends in diets, phenology, and other breeding biology variables. Within regions, trends in most variables studied have been broadly congruent, but there was often variation among regions. In particular, seabird populations in the Pacific coast zone affected by the California Current upwelling system have shown generally negative trends since the 1980s, whereas trends for populations of the same species to the north of this zone have been mainly positive. Likewise, on the east coast, trends at Arctic colonies have been decoupled from those at colonies around Newfoundland and in the Gulf of St. Lawrence, especially since the major cold water event of the early 1990s. Several long-term studies have shown an association between population events and diet and phenology changes. Diet and indicators of condition (chick growth, reproductive success) sometimes responded very rapidly to oceanic changes, making them excellent signals of ecosystem perturbations. The review highlights the effects of decadal-scale regime shifts on Canadian seabirds, confirms the value of long-term studies and supports the applicability of single-site observations to regional populations.

Environmental monitoring …, 2006

Marine birds are sensitive indicators of the condition of marine ecosystems in the Arctic, partly... more Marine birds are sensitive indicators of the condition of marine ecosystems in the Arctic, partly because they feed at the top of the arctic food chain. The Northern Ecosystem Initiative (NEI) recently supported four separate studies that investigated aspects of Arctic marine bird science which simultaneously addressed goals of the NEI to better understand northern ecosystems and their response to environmental stressors. The projects used both scientific and traditional knowledge to examine the relationship between sea-ice, contaminants, and the ecology of marine birds, and to transfer environmental knowledge to students. Results from these investigations confirm that changes are occurring in Arctic environments, and that these are captured through marine bird research. Collectively these studies provided new data that supported NEI objectives of monitoring the health of the Arctic ecosystem, and contributed to Canada's international obligations for Arctic science.

Hydrobiologia, 2009

Allochthonous nutrient subsidies play an important role in shaping biotic communities, particular... more Allochthonous nutrient subsidies play an important role in shaping biotic communities, particularly in naturally oligotrophic ecosystems such as those commonly found in the Canadian High Arctic. Seabirds have been identified as an important vector capable of transporting significant quantities of nutrients from marine to terrestrial environments. However, the influence of seabird-derived nutrients on water quality and ecosystem functioning of Arctic freshwater systems has been largely unexplored. Here, we sampled 24 ponds on Cape Vera, Devon Island (Nunavut, Arctic Canada), an area that is home to over 10,000 nesting pairs of northern fulmars (Fulmarus glacialis), in order to explore the influence of seabirds on water quality and diatom ecology. Our data reveal distinctive water chemistry changes (e.g., high pH, nutrients) and diatom assemblages (e.g., very low diversity) related to varying degrees of bird influence. Using d 15 N as a proxy of trophic level, we show that a small but significant portion of the variance in the diatom species data can be explained by seabird-derived nutrients. Although the generation of robust quantitative models predicting d 15 N from fossil diatom data was limited by the overwhelming dominance of a few taxa, this study provides evidence that seabird-derived nutrients play a critical role in influencing the water quality of Arctic ponds. Interestingly, diatom assemblage composition does not respond in a simple fashion to seabird-derived nutrients, in contrast to diatom-nutrient relationships recorded in many temperate regions.

Ecology and Society, 2007

Page 1. Copyright © 2007 by the author(s). Published here under license by the Resilience Allianc... more Page 1. Copyright © 2007 by the author(s). Published here under license by the Resilience Alliance. Gilchrist, G., and ML Mallory. 2007. Comparing expert-based science with local ecological knowledge: what are we afraid of? Ecology and Society 12(1): r1. ...

… of the Royal …, 2009

Migratory animals such as seabirds, salmon and whales can transport large quantities of nutrients... more Migratory animals such as seabirds, salmon and whales can transport large quantities of nutrients across ecosystem boundaries, greatly enriching recipient food webs. As many of these animals biomagnify contaminants, they can also focus pollutants at toxic ...

The Condor, 2009

Resumen. Los cronogramas de reproducción de las aves podrían no cambiar a una tasa suficientement... more Resumen. Los cronogramas de reproducción de las aves podrían no cambiar a una tasa suficientemente rápida como para seguir el patrón actual de cambio climático, lo que causaría una reducción en su éxito reproductivo. Esta perturbación de la sincronía se conoce como la "hipótesis del desajuste." Analizamos datos de la reproducción de Uria lomvia en la parte norte de la bahía de Hudson, Canadá, para examinar la importancia relativa del ajuste y desajuste temporal de la reproducción en determinar las tasas de crecimiento de los pichones. Entre 1988 y 2007, la fecha de ruptura y desaparición del hielo oceánico en las áreas circundantes se adelantó en 17 días, y la fecha en que los conteos de U. lomvia exhibieron un pico (un índice de la disponibilidad de alimento) se adelantó en la misma cantidad de tiempo. Sin embargo, la fecha mediana de postura de huevos se adelantó en sólo cinco días, de modo que el número de días entre la fecha de eclosión y las fechas de asistencia pico y de 50% de cobertura de hielo aumentó durante el período de estudio. El crecimiento de los pichones se redujo en aquellos años en los que los conteos de los adultos que los atendían presentaron picos a inicios de la temporada y temprano en relación con la fecha de eclosión. Estas observaciones sugieren que el momento en que tiene lugar la reproducción no se está adelantando para seguir la tasa de cambio de los eventos que suceden en el ambiente marino ártico, lo que conduce a una mayor dificultad en el aprovisionamiento de las crías. También demostramos que existe una relación entre el estado de la Oscilación del Atlántico Norte con la fecha de asistencia máxima de aves a la colonia, así como con el crecimiento de los pichones. Esto sugiere que las interacciones océano-atmósfera de gran escala influencian la disponibilidad de presas para U. lomvia, aunque el mecanismo a través del cual sucede esto todavía es desconocido. Nuestros resultados apoyan la idea de que el desajuste de los ciclos reproductivos de las aves con los picos en la abundancia de alimento es una consecuencia importante del cambio climático global.

Marine pollution bulletin, 2006

1. Mar Pollut Bull. 2006 Aug;52(8):978-82. Epub 2006 May 3. Elevated mercury levels in a declinin... more 1. Mar Pollut Bull. 2006 Aug;52(8):978-82. Epub 2006 May 3. Elevated mercury levels in a declining population of ivory gulls in the Canadian Arctic. Braune BM, Mallory ML, Gilchrist HG. Environment Canada, National Wildlife ...